Well, she claimed in Johannesburg last year that she always had a special connection with people in South Africa, and now that she's done some genetic testing, she knows why - apparently her family hailed from a Zulu tribe in South Africa.

According to the UK Guardian, wealthy African-Americans are using DNA kits to trace their roots - all the way back to Africa. Over the past few years laboratories have begun to amass a database of DNA samples from around the world, including parts of West Africa, the area from which most slaves were caught, sold and shipped to the Americas.

The technology aims either to trace a person's lineage through their genes or compile a statistical breakdown, by geographical region, of their genetic makeup. Alondra Nelson, an assistant professor of sociology and African-American studies at Yale, says results "could stretch from several thousand years to tens of thousands of years in a person's ancestry".

The science, now commercially available, has become something of a boom industry. Growing numbers of relatively wealthy African-Americans have been buying up test kits that can cost up to $350 (£200) a throw.

While other Americans could travel to towns in Ireland, Italy or Germany in search of genealogical sustenance, slavery deprived African-Americans of a clear and precise geographical bond with their own ancestry. Since slave-owners changed people's names, regularly split up families and banned reading and writing, the usual methods of keeping family histories have not been available to African-Americans until relatively recently.

But how accurate is this science? The Guardian reporter says, "I've spoken with African Americans who have tried four or five different genetic genealogy companies because they weren't satisfied with the results.They received different results each time and kept going until they got a result they were happy with."

A result that they were happy with? But how could I be happy with a result that scientifically has a huge potential to be inaccurate?

When the scientific community were asked if Oprah could truly have descended from the Zulu nation of South Africa,Professor Himla Soodyall of South Africa's National Health Laboratory Service, had this to say.

I don't know about you but I don't think I'd be using these DNA tests as the only method of finding out my ancestory.